This invention relates to a personal watercraft powered by a four cycle internal combustion engine and more particularly to a crankcase ventilating systems for such watercraft.
In many applications employing internal combustion engines as power plants, two cycle engines have been widely used. The two cycle engine has a great advantage over four cycle engines in applications where small size, relatively simple construction and high specific power outputs are desired. Thus, in many types of marine applications such as in outboard motors or in small personal watercraft, two cycle engines have been popularly employed as the prime mover.
However, with increasing emphasis on environmental protection some of the disadvantages of two cycle engines are forcing consideration of utilization of four cycle engines in their place. However, because the four cycle engine is more complex and requires some components not normally associated with two cycle engines, this presents significant problems to the engineer.
In order to improve emission control for four cycle engines, there have been proposed crankcase ventilating systems where the blow by gases and other gases in the crankcase are discharged to the atmosphere through the combustion chamber of the engine rather than directly to the atmosphere. By passing these gases through the combustion chamber, a further time, hydrocarbons can be burned and the emission of these constituents to the atmosphere can be substantially reduced. However, these components generally require not only a crankcase recirculation system but also a vapor liquid separator so that the lubricant entrained with the ventilating gases can be condensed and return to the lubricating system for reuse.
Although these types of systems are well known in automotive and other applications, the utilization of these principals in connection with marine applications and particularly with personal watercraft presents unique problems.
Specifically, a personal watercraft is a type of watercraft that is quite sporting in nature and the hull of the watercraft may assume very extreme angles even when traveling normally on the body of water. Also, these watercrafts frequently may capsize and even though they are self righting, the crankcase ventilating system is exposed to conditions which never can exist in an automotive application.
It is, therefore, a principal object of this invention to provide an improved crankcase ventilating system for a personal watercraft four cycle engine.
It is a further object of this invention to provide a crankcase ventilating system for a personal watercraft that will be able to operate effectively and sustain conditions when the watercraft may reach extreme angles in its operation in the body of water.
As has been noted, it is desirable to ensure that any lubricating oil present in the crankcase ventilating gases can be separated and returned to the lubricating system for the engine rather than being discharged to the atmosphere or introduced into the induction system of the engine. This presents a significant problem when the watercraft may become inverted in use.
It is, therefore, a still further object of this invention to provide an improved crankcase ventilating system and oil separator for personal watercraft.
It is a further object of this invention to provide watercraft vapor separator for the crankcase ventilating system that will ensure against the passage of liquid lubricant to the induction system along with the ventilating gases regardless of how the watercraft may become oriented.